The present invention relates in general to drum liner technology wherein a barrier film or bag is used to separate the contents within the liner from the drum material. More specifically the present invention relates to a flange extension for use with an externally detachable drum liner.
In a 1992 article by Douglas Larson, published in The Chemical Packaging Review, Vol. 2, No. 5, January-February, 1992, pages 32-34 the concept of an externally detachable drum liner (EDDL) was presented. Mr. Larson explains in his article that "EDDL was initially conceived as a method to facilitate the removal of tenacious semi-liquid wastes and sediments characteristic of many of the hazardous waste shipments in 55-gallon steel drums."
The value of EDDL is to enable the longer cycle of reuse for containers that might otherwise reach a point of chemical contamination due to the chemical residue left when the contents of the drum are emptied. If the residue is such that it is classified as a hazardous chemical or hazardous waste, then the chemical residue might result in the 55-gallon drum becoming 55 pounds of contaminated packaging material occupying 55 gallons of volume.
The use of a protective liner which is filled with the chemical (contents of the drum) will trap the residue in the liner leaving the drum clean and uncontaminated. This allows the drum to be handled as "clean" which greatly facilitates and simplifies its reuse or recycling. It is of course important that the liner and liner material be selected with the requisite size, strength and chemical resistance in order to handle the normal type and volume of container contents, regardless of the type or volume. While a 55-gallon drum has been referenced, the protective liner concept is also applicable to plastic and fiber drums, various containers, bags and boxes.
Another important consideration with this technology is how to secure the liner in position relative to the drum or container so that the liner can be easily attached, the liner bag filled with the desired chemical contents, and thereafter emptied and removed without a risk that the drum or container will become contaminated.
The approach described by Mr. Larson in his article and in his issued U.S. Pat. No. 5,154,308 focuses on a 55-gallon metal, open head drum and the concept of attaching the liner to the center of the lid of the drum. The drum lid is formed with a raised metal boss with an inwardly opening clearance channel or groove into which a drum plug flange is installed. A seal tube welded or soldered to the drum plug flange is used to receive a bag flange with the liner bag attached. A bag support sleeve is disposed around the seal tube and an O-ring is used to retain the EDDL to the drum lid in a way that allows the EDDL to be sealed closed and easily detached from the lid prior to removing the lid from the drum.
In the context of this EDDL system the present flange extension invention is directed to the design of the drum plug flange and seal tube components which are part of the assembly securing the liner to the lid of the drum. The value of the present flange extension invention, other than being suitable for use with the described EDDL system is its lower cost, the elimination of special flange inventories and the ability to withstand the greater heat which may be present during reconditioning of the drums.
The use of disposable liners for containers is known in the art and a variety of designs have been patented over the years. In some instances the liners are flexible and in other designs the liners are more rigid requiring disassembly of the drum for removal. In these earlier patents a variety of flange and fitting designs are disclosed, though none are believed to anticipate the present flange extension invention nor are these earlier patents regarded as being so close as to render the present invention obvious.
The following patents are representative of these earlier patented designs:
______________________________________ Patent No. Patentee Date Issued ______________________________________ 3,219,230 Housz, et al. November 23, 1965 2,987,216 Fletcher June 6, 1961 2,989,208 Gibbs, Jr. June 20, 1961 3,432,070 Carpenter, Jr. et al. March 11, 1969 4,164,304 Roberson August 14, 1979 4,552,166 Chadbourne, Sr., et al. November 12, 1985 4,635,814 Jones January 13, 1987 4,653,663 Holtsclaw March 31, 1987 4,759,459 Bailey et al. July 26, 1988 4,775,073 Webb October, 4, 1988 4,993,579 Burchett February 19, 1991 5,005,726 Robbins April 9, 1991 5,046,634 McFarlin et al. September 10, 1991 5,056,680 Sharp October 15, 1991 5,154,308 Larson October 13, 1992 3,443,735 Meijers May 13, 1969 2,338,604 Silveyra January 4, 1944 3,167,210 Carney, Jr. January 26, 1965 3,698,595 Gortz et al. October 17, 1972 3,918,605 Butler Novemebr 11, 1975 ______________________________________